FDA approves gene therapy for rare form of blindness

(HealthDay News) -- A new gene therapy to treat children and adults with a rare type of inherited vision loss has been approved by the U.S. Food and Drug Administration.

It's the first gene therapy approved in the United States for a disease caused by mutations in a specific gene, and only the third gene therapy ever approved.

People with this disorder "now have a chance for improved vision, where little hope previously existed," Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, said in an agency news release.

The drug -- Luxturna (voretigene neparvovec-rzyl) -- can be used to treat people with a condition called biallelic RPE65 mutation-associated retinal dystrophy. It causes vision loss and, in some people, may lead to complete blindness. The condition affects 1,000 to 2,000 people in the United States, according to the FDA.

"One of the best things I've ever seen since surgery are the stars. I never knew that they were little dots that twinkled," therapy recipient Mistie Lovelace said at a public hearing in October. As reported by the Associated Press, Lovelace, from Kentucky, was among several patients urging the FDA to approve the treatment.

Development of the drug began with research started about 25 years ago at the University of Pennsylvania and Children's Hospital of Philadelphia. Its co-leader was Dr. Jean Bennett, an ophthalmology professor at the university's Perelman School of Medicine and the Scheie Eye Institute.

"I've witnessed the dramatic changes in the vision of patients who would have otherwise lost their sight, and feel exhilarated that this therapy will now make a difference in the lives of more children and adults," Bennett said in a university news release.

"I'm hopeful that the path we've made with this research, with the help of our collaborators near and far, will be useful to other groups, so that other gene therapies can be developed faster and help more people with other diseases," she said.

The FDA approved the treatment after a Phase 3 study of 31 people measured how their ability to navigate an obstacle course at various light levels changed over a year. Those who took Luxturna showed significant improvements in their ability to complete the obstacle course at low light levels, compared with people who did not take the drug.

The most common problems from treatment with Luxturna were eye redness, cataract, increased intraocular pressure and retinal tear, the FDA noted.

The drug's maker, Spark Therapeutics, said it will launch a study to assess the long-term safety of Luxturna.

The FDA recommends the drug for those with a confirmed case of the condition who are 1 year and older. It's a one-time injectable treatment, the researchers said.

Like other gene therapies approved so far, this treatment will not be cheap. Spark said it would release pricing information in January but that its analysis would put the cost of the therapy at about $1 million, according to the AP.

The researchers said that through the clinical trials leading up to the drug's approval, 41 people have been treated with the drug.

"It has been amazing watching them grow up," Bennett said. Many are now able to read what's on their classrooms' chalkboards, go grocery shopping, recognize people's faces and get jobs, "among other activities that seemed impossible before," she added.

The FDA commissioner, Dr. Scott Gottlieb, said in the agency news release that the approval "marks another first in the field of gene therapy -- both in how the therapy works and in expanding the use of gene therapy beyond the treatment of cancer to the treatment of vision loss -- and this milestone reinforces the potential of this breakthrough approach in treating a wide-range of challenging diseases."

Gottlieb pointed out that "the culmination of decades of research has resulted in three gene therapy approvals this year for patients with serious and rare diseases. I believe gene therapy will become a mainstay in treating, and maybe curing, many of our most devastating and intractable illnesses," he noted.

"We're at a turning point when it comes to this novel form of therapy," he said, adding that the FDA is "focused on establishing the right policy framework to capitalize on this scientific opening."

Gottlieb said that, in the next year, the FDA would issue "a suite of disease-specific guidance documents on the development of specific gene therapy products to lay out modern and more efficient parameters -- including new clinical measures -- for the evaluation and review of gene therapy for different high-priority diseases where the platform is being targeted."